U.S. patent application number 10/567179 was filed with the patent office on 2008-10-02 for thermally and electrically conductive apparatus.
This patent application is currently assigned to TIR Systems Ltd.. Invention is credited to Ingo Speier.
Application Number | 20080239675 10/567179 |
Document ID | / |
Family ID | 36647392 |
Filed Date | 2008-10-02 |
United States Patent
Application |
20080239675 |
Kind Code |
A1 |
Speier; Ingo |
October 2, 2008 |
Thermally and Electrically Conductive Apparatus
Abstract
The present invention provides a thermally and electrically
conductive apparatus that can provide both thermal conductivity and
electrical conductivity for one or more electronic devices
connected thereto. The apparatus comprises a thermally conductive
element that is in thermal contact with one or more electronic
devices and optionally in contact with a heat dissipation system. A
portion of the thermally conductive element is surrounded by a
multilayer coating system comprising two or more layers. The
multilayer coating system includes alternating electrically
insulating and electrically conductive layers in order to provide
paths for the supply of electric current to the one or more
electronic devices. A conductive layer of the multilayer coating
system may be selectively patterned to connect to one or more
electronic devices. In this manner, the combination of an
electronic circuit carrier and a thermally conductive element can
unify thermal conductivity with the provision of power and/or
communication into a single integrated unit for use with electronic
devices.
Inventors: |
Speier; Ingo; (Saanichton,
CA) |
Correspondence
Address: |
CHRISTENSEN, O'CONNOR, JOHNSON, KINDNESS, PLLC
1420 FIFTH AVENUE, SUITE 2800
SEATTLE
WA
98101-2347
US
|
Assignee: |
TIR Systems Ltd.
Burnaby
CA
|
Family ID: |
36647392 |
Appl. No.: |
10/567179 |
Filed: |
January 5, 2006 |
PCT Filed: |
January 5, 2006 |
PCT NO: |
PCT/CA06/00011 |
371 Date: |
May 22, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60641711 |
Jan 5, 2005 |
|
|
|
Current U.S.
Class: |
361/712 ;
257/E23.004; 257/E23.006; 257/E23.102; 257/E25.02; 361/689 |
Current CPC
Class: |
F21V 3/10 20180201; H01L
23/367 20130101; H01L 2224/48227 20130101; H01L 25/0753 20130101;
H01L 23/142 20130101; H01L 33/647 20130101; F21V 29/71 20150115;
H01L 23/13 20130101; H05K 1/0272 20130101; H01L 2924/12044
20130101 |
Class at
Publication: |
361/712 ;
361/689 |
International
Class: |
H05K 7/20 20060101
H05K007/20 |
Claims
1. A thermally and electrically conductive apparatus to which one
or more electronic devices can be operatively connected, the
apparatus comprising: a) a thermally conductive element in thermal
contact with the one or more electronic devices; and b) a
multilayer coating system including two or more layers, said two or
more layers being a sequence of electrically insulating and
electrically conductive layers integrally formed on a portion of
the thermally conductive element, said electrically conductive
layers providing one or more paths for supplying electric current
to the one or more electronic devices.
2. The thermally and electrically conductive apparatus according to
claim 1, wherein one or more of the layers of the multilayer
coating system include circuit traces for connection of the one or
more electronic devices thereto, thereby providing a means for
controlling the one or more electronic devices individually or in
one or more groups of electronic devices.
3. The thermally and electrically conductive apparatus according to
claim 1, wherein the thermally conductive element is electrically
conductive, and thereby capable of providing a path for supplying
electric current to the one or more electronic devices.
4. The thermally and electrically conductive apparatus according to
claim 1, wherein one or more of the two or more layers of the
multilayer coating system are formed by deposition.
5. The thermally and electrically conductive apparatus according to
claim 1, wherein the apparatus is coupled to a support structure
comprising a circuit carrier.
6. The thermally and electrically conductive apparatus according to
claim 5, wherein the multilayer coating system is configured to
matingly connect with the circuit carrier, thereby providing one or
more electrical connections between the support structure and the
thermally and electrically conductive apparatus.
7. The thermally and electrically conductive apparatus according to
claim 6, wherein the thermally and electrically conductive
apparatus is permanently connected to the support structure.
8. The thermally and electrically conductive apparatus according to
claim 6, wherein the thermally and electrically conductive
apparatus is removably connected to the support structure.
9. The thermally and electrically conductive apparatus according to
claim 5, wherein the thermally and electrically conductive
apparatus is embedded within the support structure.
10. The thermally and electrically conductive apparatus according
to claim 5, wherein the support structure includes a heat
dissipation system.
11. The thermally and electrically conductive apparatus according
to claim 1, wherein the multilayer coating system is formed on an
end of the thermally conductive element.
12. The thermally and electrically conductive apparatus according
to claim 1, wherein the multilayer coating system is formed on a
side of the thermally conductive element.
13. The thermally and electrically conductive apparatus according
to claim 1, wherein the multilayer coating system sheaths at least
a portion of the thermally conductive element.
14. The thermally and electrically conductive apparatus according
to claim 1, wherein the thermally conductive element is a passive
thermal device selected from the group comprising heat pipe,
thermosyphon, microchannel cooler and macrochannel cooler.
15. The thermally and electrically conductive apparatus according
to claim 1, wherein the thermally conductive element is an active
thermal device selected from the group comprising thermoelectric
cooler, thermionic cooler and forced convection cooler.
16. The thermally and electrically conductive apparatus according
to claim 1, wherein the thermally conductive element has a shape
selected from the group comprising pin, planar element, curved
element, cylinder, paraboloid and ellipsoid.
17. The thermally and electrically conductive apparatus according
to claim 1, wherein the thermally conductive element has a cross
sectional shape selected from the group comprising circular,
parabolic, elliptical, prismatic and rectangular.
18. The thermally and electrically conductive apparatus according
to claim 1, wherein the thermally conductive element has a
curvilinear shape.
Description
FIELD OF THE INVENTION
[0001] The present invention pertains to the field of electronic
devices and in particular to thermally conductive circuit carriers
for use with electronic devices.
BACKGROUND
[0002] Effective thermal management is a key factor in ensuring
stable electronic device performance over a long lifetime. For
electronic devices, a high operating temperature can reduce the
lifetime of the devices and their efficacy. In addition, for
optoelectronic devices, for example light-emitting diodes (LEDs),
the junction temperature thereof can also influence the wavelength
of the emitted light. Therefore, effective thermal management of
these electronic devices is required.
[0003] Adequate cooling may not be achieved by mounting
high-powered electronic components to standard laminate boards, for
example FR4 boards. This form of board typically does not provide
sufficient thermal conductivity to remove heat from high-powered
components in order that they can operate within a desired
temperature range. As a result, secondary cooling systems for
example, heatsinks or coldplates are often used in conjunction with
these laminate boards. While adding a secondary cooling system
provides an improvement in thermal management, the thickness of a
laminate board can provide a barrier to thermal conductivity.
[0004] Incorporating thermal management into printed circuit boards
(PCBs) has enhanced the thermal flow between the heat source and
the cooling system, resulting in improved thermal management. PCBs
may include thermal vias comprising thermally conductive materials
such as copper or aluminium that are placed in direct thermal
contact with heat-producing components. In metal-core PCBs (MCPCB),
for example, the core of the board comprises a thermally conductive
metal. An MCPCB can be effective because it can be provide close
proximity between heat-producing electrical components and the
thermally conductive material, however, the thermal properties of
such modified PCB boards are typically insufficient for many of
today's applications. Hence, more advanced thermal management
systems for use with high-powered electronic components have been
developed in order to meet this need.
[0005] For example, heat pipes, thermosyphons and other two-phase
cooling devices have been designed to remove heat from high-power
electronic components in an efficient manner. In these devices,
heat is transported away from the heat source by means of a heat
conducting fluid inside the device. This device typically has two
ends, namely an evaporator end and a condenser end. At the
evaporator end the fluid evaporates upon absorption of the heat,
travels to the condenser end, and condenses upon release of the
heat, wherein this fluid may be water or some other evaporable
fluid. Heat pipes and thermosyphons are passive systems, thereby
requiring no drive circuitry or moving parts to enable their
operation. These devices have proven to be effective in moving heat
away from high-powered electronic components, particularly when
paired with a secondary cooling system. However, these devices are
typically designed to be in contact with metal-core PCBs or other
substrates that, while being thermally conductive, typically do not
enable thermal management as effectively as the heat pipes. As
such, benefits of a heat pipe are typically not optimized, as there
is a thickness of a less thermally conductive substrate between the
heat-producing element and the heat pipe.
[0006] A number of literature references disclose the use of
thermally conductive devices for use with a heat sink apparatus.
For example, U.S. Pat. No. 4,106,188 discloses a package that uses
direct cooling of high power transistors by incorporating the
components into a heat pipe. The devices are mounted on the inside
wall of a heat pipe such that they become part of the wall
structure. Electronic circuitry is included, however it does not
allow for complete functionality of the devices. In addition, the
invention does not discuss how to effectively thermally manage
mounted optoelectronic devices for example LEDs or lasers, which
are mounted on an exterior surface.
[0007] U.S. Pat. No. 6,573,536 and United States Patent Application
Publication No. 2004/0141326 disclose a light source comprising
LEDs mounted to the side of a hollow thermally conductive tube that
uses air as the cooling medium wherein the air flows in one
direction inside the tube. Electrical connections to the LEDs can
be achieved through conductive paths disposed on an electrically
insulating layer. These conductive paths can be provided by means
of one or more flexible printed circuits that are placed on the
surface of the tube. The means of placing the flexible printed
circuits on the surface of the tube however, is not disclosed.
Specifically in this prior art the thermal management design and
the electrical subsystem are conceived as two separate components
and not as one integrated system.
[0008] International Publication No. WO 03/081127 discloses a
Cooled Light Emitting Apparatus that utilizes a combination of heat
pipe and thermoelectric coolers to dissipate heat created by high
power LEDs. The LEDs are mounted on a heat spreader plate, which is
in thermal contact with a thermoelectric cooler, and which passes
the heat to a heat pipe or other heat exchange system. For this
system, the thermoelectric cooler requires a current passed through
it in order to activate the cooling function, which can result in
addition operational power of this system.
[0009] United States Patent Application Publication No.
2001/0046652 discloses a Light Emitting Diode Light Source for
Dental Curing. This publication discloses simple circuitry in the
form of one electrically conducting layer and one electrically
insulating layer that are deposited on one side of a thermally
conductive substrate possessing machined trenches that are used to
create simple circuitry. The substrate is in contact with a
thermally conductive member such as a heat pipe. The LEDs are
mounted directly to the substrate, assuming it to be electrically
conductive. Control electronics and LEDs are separated and no
reference is made to mix accompanying electronics with high-power
devices on a single substrate.
[0010] International Publication Nos. WO 2004/038759 and WO
2004/011848 disclose a method and apparatus for using light
emitting diodes for curing composites and various solid-state
lighting applications. In this invention, one or more LEDs are
mounted either directly on a heat pipe or on a substrate that is in
thermal contact with the heat pipe. The invention discloses
integrating circuitry through substrate patterning and through the
utilization of printed circuit boards in close contact with the
heat pipe.
[0011] United States Patent Application Publication No.
2004/0120162 discloses a light source that may be used as part of a
dental curing lamp. It discloses LED dies that are placed on a
substrate that is in contact with a heat exchanger. However, there
is no discussion of the integration of electronic circuitry
necessary to drive the LEDs.
[0012] U.S. Pat. No. 5,216,580 discloses an optimized integral heat
pipe and electronic circuit module arrangement. This patent
discloses a ceramic substrate carrying electronic components on one
side and metallization and a wick structure on the opposing side.
The heat pipe comprises an attached matching structure containing a
vapour chamber filled with evaporative fluid. The substrate
material of this invention is limited to ceramics, and this
invention is also limited to the placement of specific electronic
devices on such a heat pipe.
[0013] While there are many electronic device substrates that
incorporate highly thermally conductive systems, the design of such
substrates is essentially planar which limits the number of
components per useable substrate area that can be thermally
managed. Therefore, there is a need for a new apparatus that
unifies thermal conductivity and electrical conductivity with an
added possibility for enhanced package densities.
[0014] This background information is provided to reveal
information believed by the applicant to be of possible relevance
to the present invention. No admission is necessarily intended, nor
should be construed, that any of the preceding information
constitutes prior art against the present invention.
SUMMARY OF THE INVENTION
[0015] An object of the present invention is to provide a thermally
and electrically conductive apparatus. In accordance with one
aspect of the present invention there is provided a thermally and
electrically conductive apparatus to which one or more electronic
devices can be operatively connected, the apparatus comprising: a
thermally conductive element in thermal contact with the one or
more electronic devices; and a multilayer coating system including
two or more layers, said two or more layers being a sequence of
electrically insulating and electrically conductive layers
integrally formed on a portion of the thermally conductive element,
said electrically conductive layers providing one or more paths for
supplying electric current to the one or more electronic
devices.
BRIEF DESCRIPTION OF THE FIGURES
[0016] FIG. 1a illustrates a cross-sectional view of an apparatus
according to one embodiment of the present invention, wherein an
electronic device is mounted directly on the thermally conductive
element.
[0017] FIG. 1b illustrates a top view of the embodiment according
to FIG. 1a wherein the thermally conductive element has a circular
cross section.
[0018] FIG. 1c illustrates a top view of the embodiment according
to FIG. 1a wherein the thermally conductive element has a square
cross section.
[0019] FIG. 2a illustrates a cross sectional view of a thermally
and electrically conductive apparatus according to one embodiment
of the present invention, wherein multiple electronic devices are
mounted directly on the thermally conductive element.
[0020] FIG. 2b illustrates a top view of the embodiment according
to FIG. 2a.
[0021] FIG. 3a illustrates a cross sectional view of a thermally
and electrically conductive apparatus according to one embodiment
of the present invention, wherein the thermally conductive element
is embedded in a support structure for example a heat dissipation
system.
[0022] FIG. 3b illustrates a top view of the embodiment according
to FIG. 3a.
[0023] FIG. 3c illustrates a cross sectional view of a thermally
and electrically conductive apparatus according to another
embodiment of the present invention, wherein the thermally
conductive element is embedded in a support structure for example a
heat dissipation system.
[0024] FIG. 3d illustrates a top view of the embodiment according
to FIG. 3c.
[0025] FIG. 4a illustrates a cross sectional view of a thermally
and electrically conductive apparatus according to another
embodiment of the present invention, wherein an electronic device
is mounted on the multilayer coating system of the apparatus.
[0026] FIG. 4b illustrates a top view of the embodiment according
to FIG. 4a.
[0027] FIG. 5a illustrates a cross sectional view of a thermally
and electrically conductive apparatus according to another
embodiment of the present invention, wherein multiple electronic
devices are mounted on the multilayer coating system of the
apparatus.
[0028] FIG. 5b illustrates a top view of the embodiment according
to FIG. 5a.
[0029] FIG. 6a illustrates a cross sectional view of a thermally
and electrically conductive apparatus according to another
embodiment of the present invention, wherein a separation layer is
located between the support structure for example a heat
dissipation system and the layered structure thereabove.
[0030] FIG. 6b illustrates a top view of the embodiment according
to FIG. 6a.
[0031] FIG. 7a illustrates a cross sectional view of a thermally
and electrically conductive apparatus having a multilayer coating
system on one side of a board shaped thermally conductive element
according to another embodiment of the present invention, wherein
one or more electronic devices are connected to the side of the
apparatus.
[0032] FIG. 7b illustrates a cross sectional view of a thermally
and electrically conductive apparatus having a multilayer coating
system on both sides of a board shaped thermally conductive element
according to another embodiment of the present invention, wherein
one or more electronic devices are connected to the side of the
apparatus.
[0033] FIG. 7c illustrates a cross sectional view of a thermally
and electrically conductive apparatus having a multilayer coating
system on a side of a board shaped thermally conductive element
that is embedded in a support structure for example a heat
dissipation system, according to another embodiment of the present
invention.
[0034] FIG. 8 illustrates a cross sectional view of a shaped
thermally and electrically conductive apparatus according to one
embodiment of the present invention.
[0035] FIG. 9 illustrates a cross sectional view of a thermally and
electrically conductive apparatus according to another embodiment
of the present invention, wherein a connector provides a means for
coupling the thermally and electrically conductive apparatus to a
support structure.
DETAILED DESCRIPTION OF THE INVENTION
Definitions
[0036] The term "electronic device" is used to define any device
wherein its level of operation is dependent on the current being
supplied thereto. An electronic device comprises light-emitting
elements, laser diodes and any other devices requiring current
regulation as would be readily understood by a worker skilled in
the art.
[0037] The term "light-emitting element" is used to define any
device that emits radiation in any region or combination of regions
of the electromagnetic spectrum for example, the visible region,
infrared and/or ultraviolet region, when activated by applying a
potential difference across it or passing a current through it, for
example. Therefore a light-emitting element can have monochromatic,
quasi-monochromatic polychromatic or broadband spectral emission
characteristics. Examples of light-emitting elements include
semiconductor, organic, or polymer/polymeric light-emitting diodes,
optically pumped phosphor coated light-emitting diodes, optically
pumped nano-crystal light-emitting diodes or any other similar
light-emitting devices as would be readily understood by a worker
skilled in the art. Furthermore, the term light-emitting element is
used to define the specific device that emits the radiation, for
example a LED die, and can equally be used to define a combination
of the specific device that emits the radiation together with a
housing or package within which the specific device or devices are
placed.
[0038] As used herein, the term "about" refers to a +/-10%
variation from the nominal value. It is to be understood that such
a variation is always included in any given value provided herein,
whether or not it is specifically referred to.
[0039] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood by someone
of ordinary skill in the art to which this invention belongs.
[0040] The present invention provides a thermally and electrically
conductive apparatus that can provide both thermal conductivity and
electrical conductivity for one or more electronic devices
connected thereto. The apparatus comprises a thermally conductive
element that is in thermal contact with one or more electronic
devices and optionally in contact with a support structure, which
can comprise a heat dissipation system. A portion of the thermally
conductive element is surrounded by a multilayer coating system
comprising two or more layers. The multilayer coating system
includes a sequence of electrically insulating and electrically
conductive layers in order to provide paths for the supply of
electric current to the one or more electronic devices. A
conductive layer of the multilayer coating system may be
selectively patterned to connect to one or more electronic devices.
In this manner, the combination of an electronic circuit carrier in
the form of a multilayer coating system and a thermally conductive
element can unify thermal conductivity with the provision of power
and/or communication into a single integrated unit for use with
electronic devices.
[0041] The apparatus according to the present invention can be
compact in design and can achieve effective thermal management. It
can also be implemented in a modular format. Circuitry and other
electronic devices can be placed on one or more of the layers of
the multilayer coating system such that heat can additionally be
transported away therefrom, thereby enabling the provision of
thermal management to an entire system, for example. The provision
of circuit paths to the multilayer coating system can reduce the
need for external circuit boards for association with the
apparatus, thereby resulting in a reduced size of the apparatus and
allowing for increased density of these apparatuses in a prescribed
area. In one embodiment the thermally and electrically conductive
apparatus can provide an electronic circuit carrier, a support
structure for one or more electronic devices, a thermal connector
to a heat dissipation system and a mating electrical connection to
a support structure that can provide power and/or communication to
the electronic devices.
[0042] The present invention applies efficient heat removal
technology implemented in active or passive thermally conductive
elements, for example heat pipes and thermosyphons, forced
convection cooled systems including fluid cooled cold plates or
micro channel coolers, or thermoelectric cooling with the an
integrated electrically conductive multilayer coating system.
High-power electronic devices and optoelectronic devices, for
example high flux light-emitting devices, can be placed on the
thermally conductive element that can also carry the required
circuit traces and possibly further components required for the
operation of the electronic devices. The reliability of the
electronic devices can be improved as the thermally conductive
element can reduce the thermal resistance of the apparatus and
thereby provide lower electronic device operating temperature
conditions. The integration of electronic circuitry with the
thermally conductive element can provide a modular design such that
the unit can be connected to a supporting structure that can supply
power, communication and access to a heat dissipation system.
[0043] One embodiment of the present invention is illustrated in
FIG. 1a A thermally conductive element 101 is surrounded by a
multilayer coating system of alternating electrically conductive
103 and electrically insulating layers 102 and 104. The numbers and
sequences of layers of the multilayer coating system can be
different from the ones illustrated and can be dependent on the
desired functionality of the multilayer coating system. One or more
electronic devices 105 are in contact with the thermally conductive
element and further electronic devices 110 may be attached to the
multilayer coating system. The thermally and electrically
conductive apparatus can optionally be coupled to a support
structure 106, which can comprise for example a heat dissipation
system. The support structure can comprise a circuit carrier 140
which can matingly connect at connection 112 with the multilayer
coating of the thermally and electrically conductive apparatus.
Thermally Conductive Element
[0044] Heat generated by electronic devices that are in thermal
contact with a thermally conductive element can be removed and
transferred by the thermally conductive element. In one embodiment,
the thermally conductive element is connected to a heat dissipation
system.
[0045] The thermally conductive element may be formed in a number
of different shapes for example a pin, a planar element, a curved
element, a cylinder, paraboloid, ellipsoid or any other desired
shape. In addition, the thermally conductive element can have a
variety of cross-sectional shapes for example circular, parabolic,
elliptical, prismatic or rectangular. FIGS. 1b, 1c, 7a and 8
illustrate various views, of example shapes of thermally conductive
elements.
[0046] Furthermore, in different embodiments, a thermally
conductive element may be selected as one of or a combination of
heat pipes, thermosyphons, micro channel and macro channel coolers,
or other passive thermal devices, for example. Alternately, the
thermally conductive element can be configured as an active cooling
device including a thermoelectric cooler, thermionic cooler and a
forced convection cooler, for example.
[0047] The thermally conductive element can be made of an
electrically conductive or an electrically insulating material. For
example, a thermally conductive element can be made of copper, a
copper alloy, aluminium or a different metal, a ceramic material, a
polymer material, or other material provided that the selected
material is thermally conductive. When associating high-power
electronic devices with a thermally conductive element it can be
advantageous to match the thermal expansion coefficient of the
material from which the thermally conductive element is formed to
that which one or more of the electronic devices are manufactured.
For example, for an electronic device like a LED die, a material
for the thermally conductive element that can satisfy this
requirement is a combination of copper and tungsten, Cu/W.
Multilayer Coating System
[0048] A multilayer coating system is formed on the thermally
conductive element, wherein the system comprises two or more layers
and the two or more layers forming a sequence of electrically
conductive and electrically insulating layers, wherein all layers
provide a desired level of thermal conductivity. For example, an
appropriate electrically conductive layer can be formed from
copper, aluminium or other electrically conductive material. An
appropriate electrically insulating layer can be formed from a
suitable polymer, for example T-preg 1KA Dielectric material
manufactured by Thermagon, a ceramic or other electrically
insulating material known to a worker skilled in the art. One or
more of the layers of the multilayer coating system may be
patterned to provide electrical circuit traces, solder pads, vias
or other means to provide electronic connection between one or more
electronic devices and the appropriate electrically conductive
layer. For example, through the provision of circuit traces in or
on the one or more of the layers of the multilayer coating system,
electronic devices can be controlled individually or in one or more
groups. Furthermore, one or more layers may be patterned to mount
additional electronic components, or may provide an electrical
interface to external power and control, for example. As
illustrated in FIG. 2b, each electronic device connected to the
thermally conductive element, is electrically connected to an
individual circuit trace 220 thereby enabling individual control of
each electronic device.
[0049] In one embodiment of the present invention, the thermally
conductive element is a tubular heat pipe and the multilayer
coating system may be formed only on the end of the heat pipe.
Optionally, the multilayer coating system may be formed at the end
portions or all or part of the sidewall sections of the thermally
conductive element. Furthermore, the thermally conductive element
can be sheathed by a multilayer coating system. Embodiments of
these configurations are illustrated in FIGS. 1a, 2a, 3a and
4a.
[0050] The electrically insulating layers can be formed from
materials including silicon oxides, silicon nitrides, alumina, CVD
diamond or other materials as would be readily understood by a
worker skilled in the art. Optionally, ceramic slurries for example
those suitable for the fabrication of metal-core PCBs may also be
used to form the electrically insulating layers. The thickness of
the one or more electrically insulating layers in the multilayer
coating system can be designed in order that their thermal
resistance is within a desired range, thereby potentially
minimising their effect on the thermal transmission between an
electronic device and the thermally conductive element.
[0051] The layers forming the multilayer coating system can be
deposited on a thermally conductive element using a variety of
deposition techniques, for example chemical vapour deposition
(CVD), physical vapour deposition (PVD), atomic layer deposition
(ALD), dip coating, electroplating, screen printing, or other
techniques of thin-layer deposition known in the art.
[0052] In a number of different embodiments of the present
invention, the multilayer coating system provides direct access to
one end of the thermally conductive element, for example as
illustrated in FIGS. 1a, 2a and 3a. In other embodiments of the
invention, the multilayer coating system fully surrounds one end of
the thermally conductive element as illustrated in FIGS. 4a, 5a and
6a. The multilayer coating system can be configured in order that
it has a desired minimal thermal resistance to heat transfer
between the one or more electronic devices and the thermally
conductive element.
Interface
[0053] In one embodiment, the thermally and electrically conductive
apparatus can be interconnected to a support structure, which can
comprise a heat dissipation system for example. The thermally and
electrically conductive apparatus can have mechanical indexing
features to provide a reliable and consistent electrical connection
to the support structure. For example, electrical circuit traces
can be patterned such that upon insertion of the apparatus into a
suitable support structure, the indexing features ensure that the
exposed traces are in contact with corresponding traces on the
support structure that supplies power and/or communication signals
to the apparatus. A form of this indexing of the thermally and
electrically conductive apparatus is illustrated at connection 112
or 212 in FIGS. 1a and 2a respectively, wherein the multilayer
coatings are appropriately formed in order to interconnect with
desired layers on the support structure in a mating manner, for
example.
[0054] In one embodiment, the thermally and electrically conductive
apparatus is modularly attachable to a support structure, wherein
the support structure can comprise a heat dissipation system. In
one embodiment, the support structure can further comprise a
circuit board with an electrical interface to the thermally and
electrically conductive apparatus, for example. In addition, the
thermally and electrically conductive apparatus can be clamped,
screwed, bolted, or snapped, and may include keys or indexing
points such that it can be inserted into or detached from the
support structure in a predetermined and repeatable fashion. In
another embodiment, the thermally and electrically conductive
apparatus can be permanently glue bonded, soldered, or welded to a
support structure.
[0055] In one embodiment as illustrated in FIG. 9, the thermally
and electrically conductive apparatus comprises an electrical
connector 960 mounted to it that can matingly connect to an
electrical connector 970 mount on a circuit carrier 920 or
multilayer coating system that is associated with the support
structure.
[0056] The degree to which the thermally and electrically
conductive apparatus is encapsulated or inserted into a support
structure which can include for example a heat dissipation system
can vary across embodiments of the invention. For example as
illustrated by FIGS. 3a and 3c the thermally and electrically
conductive apparatus can be almost fully embedded within a support
structure.
[0057] In one embodiment, the one or more electronic devices can be
mounted directly to the surface of a thermally conductive element,
as illustrated in FIGS. 1a and 2a, thereby providing substantially
low thermal resistance to heat transfer between the electronic
device and the thermally conductive element. In this configuration,
the thermally conductive element may be electrically conductive and
therefore the portion of the thermally and electrically conductive
apparatus that is within or in contact with the support structure
can be coated with an electrically insulating layer in order to
avoid electrical connectivity between the thermally conductive
element and the support structure. An example of this configuration
of the apparatus is illustrated in FIG. 2a Additional electronic
devices 210 or electrical components can be mounted either directly
to the thermally conductive element or mounted such that they are
electrically insulated from the thermally conductive element.
[0058] In another embodiment, the one or more electronic devices
are electrically insulated from the thermally conductive element by
an electrically insulating layer of the multilayer coating system,
as illustrated in FIGS. 3a, 4a, 5a and 6a. The electrically
insulating layer or layers separating the electronic devices from
the thermally conductive element may be optimized for minimal
thermal resistance. The electrically insulating layer may or may
not extend into the region that is in contact with the support
structure as illustrated in FIGS. 2a and 5a, respectively. In the
configuration illustrated in FIG. 2a, the thermally conductive
element can be electrically active as an electrically insulating
layer of the multilayer coating system can be provided between the
thermally conductive element and the support structure.
[0059] With reference to FIG. 1a an embodiment of the present
invention is illustrated having particular regard to the cross
sectional region wherein a thermally conductive element 101 is in
contact with a support structure 106, which can include for example
a heat dissipation system. The thermally conductive element is
surrounded by a multilayer coating system of alternating
electrically conductive 103 and electrically insulating layers 102
and 104. The numbers and sequences of layers of the multilayer
coating system can be different from the ones illustrated and can
be dependent on the desired functionality of the multilayer coating
system. One or more electronic devices 105 are in contact with the
thermally conductive element. The thermally and electrically
conductive element can additionally have other electronic devices
110 attached thereto.
[0060] Another embodiment of the present invention is illustrated
in FIGS. 2a and 2b where electronic devices 205, for example
light-emitting elements, are bonded to and are in contact with one
end of the thermally conductive element 201. Connection from the
electronic devices to the electrical traces can be achieved through
wire bonding 230 or other techniques known to those skilled in the
art. It is understood that one or more of the electronic devices
can present all electrical leads in such a way that conventional
solder processes or epoxy processes can be utilized to electrically
connect the one or more electronic devices to designated pads and
or traces associated with the thermally and electrically conductive
apparatus. The second end of the thermally conductive element is
surrounded by a layer 202 of material or a compound that provides a
set of predetermined functionalities. These functionalities can
include but are not limited to electrically insulating the
thermally conductive element from the support structure 206 and
increasing the interface surface area between the thermally
conductive element and the support structure, which can comprise a
heat dissipation system. In one embodiment, the thermally
conductive element itself can be used to provide a path for the
supply of electric current to the electronic devices. Embedded in
the multilayer system can be traces 220 or vias (not shown) that
provide paths for the supply of electrical energy to the electronic
devices individually or in groups. Furthermore, additional
electronic devices 210 may be connected to the apparatus as
required.
[0061] In another embodiment of the invention as illustrated in
FIGS. 3a and 3b, the thermally conductive element 301 can be fully
embedded in the support structure 306, which can include a heat
dissipation system such that part of one end of the thermally
conductive element is available for mounting electronic devices 305
thereto via the multilayer coating system 341. The thermally
conductive element can also be embedded into the support structure
306 such that one side of the thermally conductive element is
available for mounting electronic components as illustrated in
FIGS. 3c and 3d. It is understood that in this configuration, the
thermally conductive element can be straight or bent into any shape
in the plane of the surface of the support structure, wherein this
geometric configuration of the thermally conductive element can be
dependent on the requirements of the thermally and electrically
conductive apparatus.
[0062] Furthermore, the support structure 306 can comprise a
circuit carrier 340 in the form of a PCB board or a multilayer
coating system, for example. The thermally and electrically
conductive apparatus may be removably and reusably connected to the
support structure. In this embodiment, the electronic devices may
need an enhanced heat sink capability that can be provided by this
configuration of the interconnection between the thermally
conductive element and the support structure which can comprise a
heat dissipation system. The electronic devices can be connected to
the circuit carrier provided on the support structure in various
ways for example, directly wirebonding 331 or indirectly by mating
of appropriate layers of the multilayer coating system 341 with the
circuit carrier 340 wherein an electronic device can be wirebonded
to the thermally and electrically conductive apparatus. Other
connection techniques would be known to worker skilled in the art.
The thermally conductive element can be a detachable module or an
integral part of the support structure. Furthermore, the thermally
conductive element can be an extension of the support structure,
for example.
[0063] Additional embodiments of the invention are illustrated in
FIGS. 4a, 4b, 5a, and 5b. In the embodiments of FIGS. 4a, 4b, 5a
and 5b the thermally conductive element, 401 and 501, and the
respective one or more electronic devices, 405 and 505, are
separated by a multilayer coating system. The electrically
insulating layers can achieve electrical insulation of the
thermally conductive element from the active electronic devices
while providing a desired thermal conductivity between the
electronic devices and the thermally conductive element. As
illustrated in FIG. 4a, an electronic device can be electrically
coupled to the multilayer coating system or the thermally
conductive element through wirebonding and an appropriately
designed via, for example. Alternate electrical connections would
be readily understood by a worker skilled in the art. The
multilayer coating system is fabricated from thermally conductive
materials thereby enabling heat to be transferred from the one or
more electronic devices to the thermally conductive element. In
addition, the thickness of each of the electrically conductive and
electrically insulating layers of the multilayer coating system may
be designed to improve the thermal contact between the electronic
devices and the thermally conductive element. The multilayer
coating system can have any number or sequence of electrically
insulating and electrically conductive layers such that the
electrically conductive layers provide paths for the supply of
power and/or communication to the electronic devices. As
illustrated in FIGS. 4a and 5a, the thermally and electrically
conductive apparatus can be coupled to a support structure 406 or
506, respectively, wherein the support structure can comprise a
heat dissipation system.
[0064] FIGS. 6a and 6b illustrate a variation of the configuration
illustrated in FIGS. 5a and 5b, wherein the circuit carrier 620
associated with a support structure 606 may have a separation
region 650 therebetween for the placement of additional material
layers or support structure components, for example. In this
embodiment, the electronic devices 605 can be electrically
connected to either the thermally conductive element 601 or a
conductive layer 603 of the multilayer coating system though a
wirebond 630 to an appropriately designed bond pad 603, for
example. A worker skilled in the art would readily understand
alternate electrical connection techniques.
[0065] With respect to FIGS. 7a and 7b, two more embodiments of the
invention are illustrated in which multilayer coating systems
comprising appropriate sequences of electrically conductive 703 and
electrically insulating layers 702 and 704 are in contact with a
flat thermally conductive element 701. Electronic devices 705 and
the TCE 701 can be separated by the multilayer coating system or
can be in direct contact through specific clearances or attachment
points in the multilayer coating system for heat transfer to the
thermally conductive element. In addition, electronic devices can
be connected to one or both sides of the thermally conductive
element for example wherein this can be dependent on the desired
functionality. One or a combination of sides or ends of the flat
thermally conductive element can be in contact with a heat
dissipation system and connected to a structure providing power and
communication, for example or alternately, the ends of the
thermally conductive element can be coupled to the heat dissipation
system.
[0066] In another embodiment of the present invention, the
thermally conductive element can be embedded within the heat
dissipation system as illustrated in FIG. 7c.
[0067] In another embodiment of the invention as illustrated in
FIG. 8, a thermally conductive element 801 having a predetermined
curvilinear shape is in contact with a support structure 806, which
can comprise a heat dissipation system and one or more electronic
devices 805. Under operating conditions, heat from the devices can
propagate in either direction along the thermally conductive
element to the heat dissipation system. In this embodiment, a
multilayer coating system 820 is formed on one side of the
thermally conductive element and comprises a mating interface
connection with a circuit carrier 830 for example a circuit board
or multilayer coating system that is associated with the support
structure 806. It would be readily understood that the multilayer
coating system on the thermally conductive element can cover both
sides thereof. In addition, the circuit carrier associate with the
support structure can be configured based on the multilayer coating
system, for example the circuit carrier may be only provided on one
side of the support structure.
[0068] FIG. 9 illustrates another embodiment of the present
invention, wherein electrical connection of the electronic devices
605 associated with the thermally conductive element 601 to a
circuit carrier 920 or multilayer coating system associated with
the support structure, can be provided by electrical connectors of
the surface mount or thorough hole connector configuration. The
format of these types of connectors would be readily understood by
a worker skilled in the art. In this embodiment a first connector
part 960 is coupled to the thermally and electrically conductive
apparatus and can be removably and reusably coupled to a mating
second connector part 970, which is coupled to the circuit carrier
920. In one embodiment, in addition to providing electrical
contact, these connectors can also provide mechanical mounting
features, for example as is provided by snap-on connectors. As
would be readily understood, the connector can be mounted at a
desired location on the thermally and electrically conductive
apparatus or can cover part of the entire outer perimeter of the
thermally and electrically conductive apparatus. Furthermore,
multiple forms of these connectors can be used.
[0069] As illustrated in the Figures, the sizes of layers or
regions are exaggerated for illustrative purposes and, thus, are
provided to illustrate the general structures of the present
invention. Once again, as stated previously, various aspects of the
present invention are described with reference to a layer or
structure being formed. As will be appreciated by those of skill in
the art, references to a layer being formed "on" another layer or a
thermally conductive element contemplates that additional layers
may intervene. Furthermore, relative terms such as beneath may be
used herein to describe one layer or regions relationship to
another layer or region as illustrated in the Figures. It will be
understood that these terms are intended to encompass different
orientations of the device in addition to the orientation depicted
in the Figures. For example, if the device in the Figures is turned
over, layers or regions described as "beneath" other layers or
regions would now be oriented "above" these other layers or
regions. The term "beneath" is intended to encompass both above and
beneath in this situation.
[0070] It would be readily understood by a worker skilled in the
art that while the Figures illustrate a particular number of
layers, each of these identified layers can be formed by a
plurality of layers depending on the targeted application or
optionally there may be fewer layers within the structure.
[0071] It is obvious that the foregoing embodiments of the
invention are exemplary and can be varied in many ways. Such
present or future variations are not to be regarded as a departure
from the spirit and scope of the invention, and all such
modifications as would be obvious to one skilled in the art are
intended to be included within the scope of the following
claims.
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